Flow regulating implant, method of manufacture, and delivery device

ABSTRACT

An implant includes a tube for permitting fluid flow. A flow controlling rod may be inserted within the tube passage. One or more holes around the circumference of the tube may be selectively permanently or temporarily occluded to give desired flow characteristics. A delivery device for implanting the implant may include a central bore in which a retractable wire is located. The retractable wire penetrates a tube passage of the implant. After the implant is in position in the eye, the retention wire is retracted out of the implant. In a method for manufacturing an implant, two tubes of different diameters are utilized. The smaller tube fits inside the longitudinal bore of the larger tube. When the tubes are cut, the smaller tube forms the tube of the implant and the remaining portions of the larger tube form the retention projection and/or disk of the implant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of application Ser. No. 12/691,176,filed on Jan. 21, 2010, which is a Continuation of application Ser. No.11/952,819, filed on Dec. 7, 2007, now U.S. Pat. No. 7,670,310, which isa Continuation of application Ser. No. 10/314,324, filed on Dec. 9,2002, now abandoned, which is a Divisional of application Ser. No.09/729,050, filed on Dec. 4, 2000, now U.S. Pat. No. 6,510,600, which isa Divisional of application Ser. No. 08/975,386, filed on Nov. 20, 1997,now U.S. Pat. No. 6,203,513, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The invention relates generally to medical implants used to regulate theflow of fluids within the body. The invention may be applied, forexample, to ophthalmic implants for treatment of glaucoma. The inventionalso relates to methods of manufacturing such implants and to deliverydevices for implanting such implants.

BACKGROUND OF THE INVENTION

Medical implants used to regulate the flow of fluids within the humanbody are known and used.

One application for the use of such implants is in the treatment ofglaucoma. Glaucoma is an eye condition characterized by an increase inthe intraocular pressure (IOP) of the eye to an abnormal level. A normaleye maintains a proper IOP by the circulation within the eye of aqueoushumor—aqueous humor is secreted from the ciliary body, passes throughthe pupil into the anterior chamber of the eyeball, and is filtered outof the eyeball via the trabeculum and the Canal of Schlemm. Withglaucoma, the aqueous humor excretory pathway is blocked, the aqueoushumor cannot pass out of the eyeball at an adequate rate, the IOP rises,the eyeball becomes harder, and the optic nerve atrophies by thepressure applied on its fibers leaving the retina. A characteristicoptic neuropathy develops, resulting in progressive death of theganglion cells in the retina, restriction of the visual field, andeventual blindness. Advanced stages of the disease are characterizedalso by significant pain.

Glaucoma treatment, if initiated early in the course of the disease, canprevent further deterioration and preserve most of the ocular functions.The goal of glaucoma treatment is to reduce the IOP to a level which isconsidered safe for a particular eye, but which is not so low as tocause ocular malfunction or retinal complications.

One type of glaucoma treatment is filtration surgery, which provides analternate route for aqueous humor to exit the anterior chamber of theeyeball and enter the sub-conjunctival space, thereby lowering the IOP.In full thickness operations a fistula is created through the limbalsclera, connecting directly the anterior chamber of the eyeball and thesub-conjunctival space. Full thickness operations provide long-lastingcontrol of IOP; however, excessive loss of aqueous humor from theeyeball during the early postoperative period frequently leads tohypotony.

In guarded filtration surgery (trabeculectomy), a fistula createdthrough the limbal sclera is protected by an overlying partial thicknesssutured scleral flap. The scleral flap provides additional resistance toexcessive loss of aqueous humor from the eyeball, thereby reducing therisk of early postoperative hypotony. However, trabeculectomy may resultin higher eventual IOP and increased risk of late failure of filtration,compared with full thickness operations.

In accordance with one recently introduced procedure, a full thicknessfiltering fistula may be created by a holmium laser probe, with minimalsurgically induced trauma. After retrobulbar anesthesia, a conjunctivalincision (approximately 1 mm) is made about 12-15 mm posterior to theintended sclerostomy site, and a laser probe is advanced through thesub-conjunctival space to the limbus. Then, multiple laser pulses areapplied until a full thickness fistula is created. This technique hassometimes resulted in early hypotony on account of a difficulty incontrolling the sclerostomy size. In addition, early and late irisprolapse into the sclerostomy has resulted in abrupt closure of thefistula and eventual surgical failure. Further, despite its relativesimplicity, the technique still necessitates the use of retrobulbaranesthesia to avoid pain caused by the laser applications. The injectionof anesthetic material close to the already damaged optic nerve maysometimes lead to further visual damage. A further disadvantage of thisprocedure, as well as other types of glaucoma filtration surgery, is thepropensity of the fistula to be sealed by scarring.

Various attempts have been made to overcome the problems of filtrationsurgery, for example, by using ophthalmic implant devices. Typicalophthalmic implants utilize drainage tubes so as to maintain theintegrity of the openings formed in the eyeball for the relief of theIOP.

Typical ophthalmic implants suffer from several disadvantages. Forexample, the implants typically utilize a valve mechanism for regulatingthe flow of aqueous humor from the eyeball; defects in and/or failure ofsuch valve mechanisms could lead to excessive loss of aqueous humor fromthe eyeball and possible hypotony. The implants also tend to clog overtime, either from the inside by tissue, such as the iris, being suckedinto the inlet, or from the outside by the proliferation of cells, forexample by scarring. Additionally, the typical implant insertionoperation is complicated, costly and takes a long time.

U.S. Pat. No. 3,788,327 to Donowitz et al. shows a prior art implantutilizing a valve mechanism for regulating the flow of aqueous humorfrom the eyeball. As stated above, defects in and/or failure of such avalve mechanism could lead to excessive loss of aqueous humor from theeyeball and possible hypotony. Additionally, both the inlet opening andthe outlet opening in the implant shown in U.S. Pat. No. 3,788,327 maybe susceptible to clogging—the inlet opening by the iris and the outletopening by scarring. Finally, implantation of an implant according toU.S. Pat. No. 3,788,327 may involve the separate steps of firstproviding a tract for receiving the implant and/or suturing the implantonce it is in place, which add time and possible complications to theoperation.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved implant toregulate the flow of fluids within the body. The invention may beapplied, for example, to an ophthalmic implant which may be implantedinto the eyeball for the treatment of glaucoma. It is a further objectof the invention to provide a method of manufacturing such an implantand a delivery device for implanting such an implant.

In one embodiment of an improved implant in accordance with theinvention, an intraocular implant is provided to be implanted in theeyeball. The implant includes a tube having an inlet end, an outlet end,and a tube passage therebetween for permitting aqueous humor to flow outof the eyeball, and a disk connected to the tube at the outlet end ofthe tube. The tube passage may have a cross-sectional area sufficientlysmall to inhibit the flow of aqueous humor through the tube passage. Aflow controlling wire or rod may be inserted within the tube passage toprovide further control over the flow. The configuration of the flowcontrolling rod may be selected in accordance with the desired flowcharacteristics. The configuration may be chosen to prevent flow whenthe IOP is below a threshold amount.

The disk, which is designed to be located underneath the conjunctiva,may have an outer rim for forming a reservoir having an enlargedcross-sectional area relative to the cross-sectional area of the tubepassage. When aqueous humor flows through the tube passage, a bleb ofaqueous humor forms under the conjunctiva so that the bleb and theelasticity of the conjunctiva assist in regulating the flow of aqueoushumor through the tube as a function of the IOP.

To prevent clogging of the implant, the tube at its inlet end may beprovided with a beveled surface which faces away from the iris when theimplant is inserted. Additionally, one or more circumferential holes maybe provided along the tube for allowing aqueous humor to flow into thetube passage even if the axial inlet opening is blocked. The hole orholes may be selectively permanently or temporarily occluded to givedesired flow characteristics.

To prevent clogging at the outlet end, the disk may have an outer rim asdescribed above which raises the conjunctiva away from the axial outletof the tube passage to allow outflow. One or more inner uprights (whichmay be in the form of an inner rim) may also be provided on the disk forthis purpose. Clogging is further avoided by implanting the implantunder the conjunctiva at a distance away from an insertion slit in theconjunctiva, such that healing of the slit does not cause scar tissue toform in the area of the axial outlet opening of the implant.

Implantation may be facilitated by further features of the implant. Forexample, the implant may have one or more retention projections (forexample, in the form of a spur, flange, or plate). The retentionprojection may be rigid, or it may be made of an elastic material suchthat it is able to be flexed inward against the tube during penetrationthrough the sclera. Alternatively, the retention projection may bedesigned to lie initially relatively flat against the tube for easierpenetration through the sclera and to prevent tearing of the sclera,with a mechanism for extending the retention projection outwardly whenthe implant is implanted in the eyeball. For example, the retentionprojection may be extended outwardly by a separate expansion tool or maybe constructed of a shape memory material, such as PMMA or nitinol, sothat it is extended outwardly when subjected to the heat of the eyeball.One or more such retention projections are sufficient to reliably anchorthe implant in the eyeball without the need for sutures, saving time andcosts.

Implantation may also be facilitated by the provision of one or moremarkers on the implant visible through the cornea upon passing throughthe sclera. For example, a circumferential hole as described above mayserve as a marker; alternatively, the marker may be some other suitablevisible mechanism, such as a scratch or colored mark on the tube. Thevisibility of the marker lets the doctor know that the marker has passedthrough the sclera, indicating that the implant is in place.

Implantation of an implant may be performed by use of a delivery devicecomprising a handle and a rod-like instrument, for example a needle orprobe, for carrying the implant for insertion. The delivery device has atip for insertion into the tube passage of the implant and a suitableretention mechanism for preventing the implant from moving up thedelivery device during implantation. The retention mechanism may also beconstructed to prevent the implant from rotating during implantation toinsure proper orientation of the implant. The delivery device mayadditionally have a suitable expansion tool for extending one or moreretention projections of the implant outwardly once the projection orprojections have penetrated through the desired tissue.

In an embodiment of a delivery device according to the invention, therod-like instrument has a central bore in which is located a retractablewire. The retractable wire penetrates a tube passage of the implant whenthe implant is attached to the delivery device. A hook on the deliverydevice prevents the implant from moving down the wire. After the implantis in position in the desired implantation site, the retention wire isretracted out of the implant. With the retention wire retracted, theimplant is then free to slide away from the hook, allowing the deliverydevice to be withdrawn, leaving the implant in place.

In one method of implanting an implant according to the invention, asmall slit is cut in a portion of the conjunctiva which normally lies ata distance away from the intended implantation site. As the implantitself is very small, the slit also may be very small, for example about2 mm in length or less. The small size of the slit as well as itspositioning at a distance away from the implantation site, for exampleabout 10 mm, helps prevent contamination of the sclerostomy site andreduces the risk of infection.

The implant is placed through the slit, directed to the implantationsite, and inserted into the sclera at the implantation site. The scleramay be pierced either by a needle-like tip of the tube of the implantformed by a beveled surface at the inlet end of the tube as describedabove or by the tip of a needle of the delivery device which carries theimplant. Thus, the implant may be inserted directly into the eyeballwithout the need for any separate piercing step, resulting in cost andtime savings.

In a method for manufacturing an intraocular implant according to theinvention, two tubes of different diameters are utilized. The smallertube is able to fit inside the longitudinal bore of the larger tube.When the tubes are cut, the smaller tube forms the tube of the implantand the remaining portions of the larger tube form the retentionprojection and disk of the implant.

An intraocular implant according to the invention provide the advantagesof a full thickness fistula, while avoiding the limitations of thestandard trabeculectomy. An implant according to the invention may bevery small and implantable without surgery. No surgery room orhospitalization is necessary, thereby reducing costs. Implantation isminimally invasive, simple and quick, requiring only local anesthesia.Retrobulbar anaesthesia is not necessary, and thus iatrogenic damage tothe optic nerve is avoided. There is no need to perform an iridectomy,and thus aqueous flow is maintained, lens nourishment is unaffected, andthe likelihood of cataracts developing as a result of the procedure isreduced.

An implant according to the invention has other applications aside fromthe field of intraocular implants. For example, the implant may be usedfor drainage of a hydrocele sac, regulating flow between the hydrocelesac and the subcutaneous scrotum. As will be appreciated by persons ofordinary skill in the art, other applications of an implant inaccordance with the invention are possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a first embodiment of anintraocular implant shown inserted in an eyeball;

FIG. 2 is an enlarged perspective view of the intraocular implant ofFIG. 1;

FIG. 3 is a view similar to FIG. 2, with part of the intraocular implantcut away to show a sectional view thereof;

FIG. 4 is an enlarged perspective view of a disk portion of theintraocular implant of FIG. 1;

FIGS. 5 through 7 illustrate the action of the conjunctiva duringoperation of the intraocular implant of FIG. 1, with FIG. 5 showing astage of operation without a bleb formed, FIG. 6 showing a formation ofthe bleb, and FIG. 7 showing further formation of the bleb;

FIGS. 8 through 10 illustrate a delivery device and insertion of theintraocular implant of FIG. 1 into an eyeball, with FIG. 8 showing thedelivery device and implant before insertion, FIG. 9 showing thedelivery device and implant being placed through a slit in theconjunctiva, and FIG. 10 showing the implant after insertion with thedelivery device withdrawn;

FIG. 11 is an enlarged perspective view of a second embodiment of anintraocular implant with part of the intraocular implant cut away toshow a sectional view thereof;

FIG. 12 is a top view of the intraocular implant of FIG. 11, showing adisk portion of the implant;

FIG. 13 illustrates a delivery device and insertion of the intraocularimplant of FIG. 11 into an eyeball;

FIG. 14 is a schematic cross-sectional view of the intraocular implantof FIG. 11, shown inserted in an eyeball;

FIGS. 15 and 16 illustrate a third embodiment of an intraocular implantwith FIG. 15 showing the implant prior to attachment of a retentionplate and FIG. 16 showing the implant after attachment of the retentionplate;

FIGS. 17 through 19 illustrate successive steps in a method ofmanufacturing an intraocular implant according to an embodiment of theinvention, with FIG. 17 showing an outer tube cut in an initial phase ofthe manufacturing process, FIG. 18 showing the outer tube joined to aninner tube, and FIG. 19 showing the finished intraocular implant;

FIG. 20 illustrates an intraocular implant according to the inventionwith a flow controlling wire or rod in the tube passage;

FIGS. 21A through 21D illustrate four variations of cross-sections for aflow controlling rod;

FIG. 22 illustrates an intraocular implant with a threaded flowcontrolling rod;

FIG. 23 illustrates an intraocular implant with a tapered flowcontrolling rod;

FIG. 24 illustrates an intraocular implant with an adjustable flowcontrolling rod;

FIG. 25 illustrates an intraocular implant with selectively occludedside holes;

FIG. 26 illustrates an intraocular implant with a flexible flowcontrolling rod;

FIG. 27 illustrates an intraocular implant with a flow controlling rodbiased against a spring;

FIG. 28 illustrates the end of an embodiment of a delivery deviceaccording to the invention and an implant attached to the deliverydevice; and

FIG. 29 illustrates a view similar to that of FIG. 28, with a retentionwire of the delivery device retracted from the implant.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an intraocular implant 30, implanted in an eyeball10. The implant 30 comprises a needle-like tube 32 and a disk 34. Theplane of the disk 34 forms an angle with the tube 32 that corresponds tothe angle between the surface of the sclera 12 and the axis of insertionof the implant 30. The implant 30 is inserted in the sclera 12 of theeyeball 10, in the limbal area 14 adjacent to the cornea 16, andprotrudes into the anterior chamber 20 adjacent the iris 22. The implant30 is inserted so that the disk 34 is placed on a surface of the sclera12 underneath the conjunctiva 18. The implant 30 may be placed above orbelow the Tenon's capsule (not shown). It will be appreciated by personsof ordinary skill in the art that the exact location for inserting theimplant 30 is not restricted to that shown, and may be any othersuitable position, such as behind the iris 22.

FIG. 2 shows an enlarged perspective view of the implant 30 of FIG. 1,and FIG. 3 shows a similar view, with part of the implant 30 cut away.The tube 32, which may take the form of a modified standard retrobulbartip, has an inlet end 40, an outlet end 50, and a tube passage 38extending therebetween, with the tube passage 38 having an axial inlet41 and an axial outlet 51. The disk 34 is connected to the tube 32 atits outlet end 50. The entire implant is very small; for example thetube 32 may have a length of about 2 mm and a width of about 0.5 mm, andthe disk 34 may have a diameter of about 1 mm and a thickness of lessthan 0.1 mm.

The tube passage 38 has a cross-sectional area sufficiently small toinhibit the flow of aqueous humor through the tube passage. In oneembodiment, for example, the cylindrical tube passage 38 has a diameterof about 300 micrometers. By using a specified internal cross-sectionalarea for the tube passage, excessive loss of aqueous humor from theeyeball is prevented.

When the IOP is above a threshold amount, for example about 5 mm Hg,aqueous humor drains from the anterior chamber 20 of the eyeball 10through the axial inlet 41 and one or more circumferential holes 42,through the tube passage 38, and into the space under the conjunctiva18. The circumferential holes 42 may take any suitable form; forexample, they may be in the form of circular openings whose combinedcross-sectional area is equal to the cross-sectional area of the tubepassage 38. The circumferential holes 42 prevent the tube passage 38from becoming clogged at its inlet end because, even if the iris 22obstructs the axial inlet 41, aqueous humor can still pass through thecircumferential holes 42. In the event the axial inlet 41 is obstructed,the circumferential holes 42 also serve to cause a back pressure in thetube passage 38 to unclog the axial inlet 41. The circumferential holes42 serve the additional purpose of insuring a proper insertion depth ofthe implant 30, as the upper hole is visible during implantation afterpenetration through the sclera and thus can be used as a marker. Toserve this function, any other suitable marker (such as a scratch orcolored mark) may be used.

The inlet end 40 of the tube 32 has a needle-like tip formed by abeveled surface 36, angled sharply for easy insertion into the eyeball.The beveled surface 36 increases the area of the axial inlet 41 toenlarge the entrance to the tube passage 38. The beveled surface 36 isdesigned to face away from the iris 22 to reduce the possibility ofobstruction of the axial inlet 41. Because the disk 34 is designed torest against the sclera 12 and the beveled surface 36 is designed toface away from the iris 22, the beveled surface 36 lies in a plane whichis angled opposite to the plane in which the disk 34 lies.

The tube 32 may have one or more retention projections in the form ofone or more spurs 52 provided integrally with it for retaining theimplant 30 in the eyeball 10 after insertion. Alternatively, theretention spur 52 may be made as a separate part connected to the tube32 by, for example, welding or brazing. The retention spur 52 may berigid, or it may be flexible such that it bends toward the tube 32during penetration of the sclera and springs outward to its originalshape after passing through the sclera. Alternatively, the retentionspur 52 may be designed for plastic deformation by a separate expansiontool (for example, a balloon) once it is in the eyeball 10, or theretention spur 52 may be constructed of a shape memory material, such asPMMA or nitinol, such that the spur is flat against the tube when coolbut expands to its final shape when subjected to the heat of the eyeball10.

The disk 34, shown enlarged in FIG. 4, comprises a base 44, an outer rim46, and a plurality of inner uprights 48. The areas between the uprights48 constitute passageways 56 for the transverse flow of aqueous humor.The base 44 and outer rim 46 define a reservoir 54 such that, inoperation, the aqueous humor flows out of the axial outlet 51 of thetube passage 38, between the uprights 48, and into the reservoir 54. Thepassageways 56 may be considered as part of the reservoir 54. Theenlarged cross-sectional area of the reservoir 54 as compared to thecross-sectional area of the tube passage 38 provides a larger area forabsorption of the aqueous humor by the conjunctiva 18 and also acts inconjunction with the elasticity of the conjunctiva 18 to assist inregulating the flow of aqueous humor through the implant 30 as afunction of the IOP.

FIGS. 5 through 7 illustrate the action of the conjunctiva 18 duringoperation of the implant 30, in which it can be seen that the aqueoushumor which flows out of the tube passage forms a “bleb” 24 below theconjunctiva 18. It will be appreciated by persons having ordinary skillin the art that a higher IOP results in a higher flow rate through theimplant 30, and a greater force of the aqueous humor on the conjunctiva18.

In addition to defining the reservoir 54, the outer rim 46 of the disk34 serves the additional purpose of raising the conjunctiva 18 away fromthe axial outlet 51 to prevent clogging of the tube passage 38. Theinner uprights 48 also serve this purpose.

The shape of the disk 34 may be, but is not limited to, an ellipse, andit will be appreciated by persons having ordinary skill in the art thatit may conform to any shape which allows the implant to fit under theconjunctiva 18 and which regulates the IOP. The size and/or shape of thedisk 34 and/or the angle between the disk 34 and the tube 32 can also bechanged in order to use different implants for different persons' eyes.

FIGS. 8 through 10 illustrate a delivery device 60 and a method ofinserting the intraocular implant 30 into an eyeball. The implant 30 isfirst attached to the delivery device 60, having a handle 62 and asuitable rod-like instrument 64 such as a needle or probe. The rod-likeinstrument 64 has a tip 70 for penetrating a tube passage of the implant30 and a retention mechanism for preventing the implant from moving upthe delivery device during implantation, for example in the form of anabutment surface 68 having an angle generally corresponding to that ofthe disk 34. This configuration also prevents rotation of the implant 30on the delivery device 60, thereby insuring proper orientation of theimplant in the eyeball. The retention mechanism may also include one ormore projections for extending inside the outer rim and/or between theinner uprights on the disk 34. In an alternative embodiment, theretention mechanism may be the tip of the rod-like instrument,constructed to engage the inside of the tube passage of the implant witha friction fit, thereby preventing the implant from moving up thedelivery device during implantation.

A delivery device 60 in which the rod-like instrument is a needle 65 isillustrated in FIG. 9. In that illustrated embodiment, the deliverydevice 60 is similar to a standard medical syringe having a housing anda needle 65 with a bore 67. The front tip 69 of the needle 65 isconfigured as an abutment surface having an angle generallycorresponding to that of the disk 34. The bore 67 of the needle 65 has atip in the form of a plug 71 which is configured to have across-sectional shape corresponding to that of the tube passage 38. Theimplant 30 is placed over the plug 71, with the end of the plug 71projecting into the tube passage 38, and with the front tip 69 of theneedle 65 abutting against the disk 34. The plug 71 blocks the tubepassage 38 during implantation.

To insert the implant 30 into the eyeball 10, a small slit 26 is cut ina portion of the conjunctiva 18 which normally lies at a distance awayfrom a portion 28 of the conjunctiva 18 which normally covers theintended implantation site. A small slit distanced away from theimplantation site, for example a 1-2 mm slit about 5-15 mm away from theimplantation site, reduces the possibility of aqueous humor flowing outof the conjunctiva through the slit, reduces the possibility ofinfection, reduces the possibility of scarring over the axial outlet ofthe implant, and facilitates closing and healing.

The implant 30, by delivery device 60, is passed through the slit 26,under the conjunctiva 18, to the implantation site in the sclera 12.FIG. 9 shows the advancement of the implant only schematically; it willbe appreciated that in practice the implant is directed from the slit tothe implantation site generally along the surface of the sclera, suchthat the longitudinal axis of the implant is generally parallel to thesurface of the sclera. Upon reaching the implantation site, the implantis tilted for penetration into the sclera. The acute angle of theneedle-like tip formed by the beveled surface 36 of the implant 30ensures that the implant 30 enters the sclera 14 easily. The needle-liketip penetrates through the sclera 12 into the anterior chamber 20 of theeyeball 10, while the disk 34 is pushed up against the sclera 12.

When the implant 30 is in place, as shown in FIG. 10, the retention spur(or spurs) 52 anchors the implant 30 in the eyeball 10 and prevents theimplant 30 from sliding out as the delivery device 60 is withdrawn. Theretention spur 52 also prevents the implant 30 from slipping out once inplace.

It will be appreciated by persons having ordinary skill in the art thatthe insertion of the implant is not restricted to the method describedabove, and it may be inserted by any of several methods known in theart. The delivery device may comprise an ‘internal’ or ‘external’needle. A straight or twisted guide wire, known in the art, may also beused to guide the delivery device to its precise position. To easeinsertion, the delivery device may be vibrated, or a lubricant, such asmedical paste or gel, can be spread onto the delivery device.Additionally, after implantation of the implant a suitable fibrosisinhibiting compound (e.g. 5FU, mitomycin) may be applied to theimplantation site.

FIG. 11 shows an alternative embodiment of an intraocular implant 130.The implant 130 comprises a tube 132 attached to an elliptical disk 134.The tube 132 has an inlet end 140, an outlet end 150, and a tube passage138, with the tube passage 138 having an axial inlet 141, an axialoutlet 151, and circumferential holes 142 to drain the aqueous humorfrom the anterior chamber 20 of the eyeball 10 into the space under theconjunctiva 18.

The distal end 152 of the tube 132 has a partially conical shape. Aplurality of retention projections in the form of retention flanges 158are formed on the outer circumference of the tube 132, approximatelyparallel to the disk 134, to act as anchors to retain the implant 130 inthe eyeball.

As shown in the enlarged view in FIG. 12, the disk 134 comprises anelliptical base 144, an outer rim 146, and an inner upright curved toform an inner rim 148, defining therebetween a reservoir 154. Aplurality of “U”-shaped passageways 156 are formed in the inner rim 148for allowing aqueous humor to flow from the axial outlet 151 into thereservoir 154. The outer rim 146 and the inner rim 148 prevent theconjunctiva 18 from clogging the axial outlet 151.

As shown in FIG. 12, the disk 134 is elliptical in shape. The longeraxis of the disk 134 is approximately twice the diameter of the tube132, and the disk 134 is eccentrically displaced relative to the tube132. The elliptical shape and placement of the disk 134 allows a wideanchoring area for the implant 130 and maximizes the outlet drainagearea on the longer axis of the ellipse. The shorter axis of the ellipseenables the implant 130 to fit within the narrow space under theconjunctiva 18.

FIG. 13 illustrates a delivery device 160 and a method of inserting theintraocular implant 130 into an eyeball. The implant 130 is slidablyfixed over a needle 164 of the delivery device 160, which, similar to astandard medical syringe, has needle 164 attached to a housing 162. Thetip 174 of needle 164, which passes through the implant 130, is acutelyangled so that the tip 174 is generally in line with the angle of thelower part of the implant 130.

A front surface of the delivery device 160 is formed as an abutmentsurface angled to match the angle of the disk 134 and further comprisesan indent 172 to hold the implant 130 in place during implantation. Theshape of the delivery device 160 and the angled surface of the disk 134prevent the implant 130 from rotating during implantation.

The delivery device 160 shown in FIG. 13 is used in a manner similar tothat described above with reference to FIGS. 8 through 10. In thisembodiment, however, the acute angle of the needle tip 174 pierces thesclera. The angled inlet end of the implant device 130 follows theneedle tip 174 through the sclera 12, into the anterior chamber 20 ofthe eyeball. As shown in FIG. 14, the retention flanges 158 anchor theimplant 130 in position and prevent the implant 130 from sliding out asthe delivery device 160 is withdrawn. The anchorage of the retentionflanges 158 also prevents the implant 130 from slipping out once inplace.

FIGS. 15 and 16 illustrate a third embodiment of an intraocular implant.This embodiment is similar to that shown in FIGS. 1 through 10, with theexception that a separately attached retention projection in the form ofa retention plate 252 is used for anchoring instead of the retentionspur 52. The retention plate is inserted into a groove 253 in the tubeof the implant 230 and may be fastened by any suitable means, forexample by welding in the case of an implant 230 constructed ofstainless steel.

An implant constructed in accordance with the invention may bemanufactured entirely from or covered with any suitable material such asstainless steel, silicon, gold, nitinol, Teflon, tantalum, PMMA, or anyother suitable plastic or other material. The implant may also be coatedwith heparin or any other suitable biologically active compound.

Manufacture of an implant in accordance with the invention may becarried out according to the following process. The tube may be formedfrom the tip of a standard stainless steel hypodermic needle. Using anEDM machine, small holes are drilled proximate the tip of the needle toform the circumferential holes. At a distance from the tip correspondingto the desired length of the tube, the needle is cut at the appropriateangle to correspond to the desired angle of the disk. The side of theneedle is then undercut to form a projection which can be later bentoutwardly to form the spur.

The disk may be chemically etched from a stainless steel sheet accordingto the following process. A pattern of the disk is drawn on a computeraided design (CAD) system and plotted on a transparent film using alaser plotter. Plottings are made of both the upper side and the lowerside of the disk. The plotting for the upper side, for example, includesthe outer rim and the inner uprights; the plotting for the lower side,for example, includes the base of the disk.

A layer of photoresist is adhered to both surfaces of the stainlesssteel sheet. The photoresist is then exposed to UV light through thefilm on which the plottings are made. The areas of the sheet which areblocked by the plottings are not exposed. The photoresist which has beenexposed to UV light is then chemically removed.

Using an etching chemical, the stainless steel sheet is then etched, sothat the chemical eats away the areas of the sheet from which thephotoresist has been removed. The etching is time-controlled such thatthe chemical takes away material only to a predetermined depth.

By use of a plotting for the upper side which includes the outer rim andthe uprights, the chemical on the upper surface of the sheet takes awaymaterial on the outside of the disk, in the reservoir including betweenthe uprights, and in the center of the disk which is to receive thetube. Because the etching is time-controlled, the chemical acting on thetop of the sheet takes away material only part way through the thicknessof the sheet. By use of a plotting for the lower side which includes thebase of the disk, the chemical on the lower surface of the sheet takesaway material on the outside of the disk and in the center of the diskwhich is to receive the tube. The chemical acting on the bottom of thesheet takes away material part way through the thickness of the sheet.Because of action from both the top and the bottom, the material on theoutside of the disk and in the center of the disk which is to receivethe tube is completely taken away by the etching process through theentire thickness of the sheet. A small projection may be left on theoutside of the disk during the etching process to prevent the disk frombeing dislodged from the sheet.

An alternative method for manufacturing an implant according to theinvention is illustrated in FIGS. 17 through 19. FIG. 17 shows aninitial step of the process in which an outer tube 74 having alongitudinal bore is cut into the illustrated pattern. The outer tube 74may have, for example, an outer diameter of about 1 mm and an innerdiameter (i.e., a diameter for its longitudinal bore) of about 400micrometers. In the illustration, the outer tube 74 has been cut intotwo pieces 76 and 78; however, it should be recognized by personsskilled in the art that the two pieces 76 and 78 need not be completelyseparated. For example, the bottom half of the tube 74 could be leftintact between the two pieces, leaving a connection piece in the form ofa half-cylinder between the piece 76 and the piece 78.

In a next step of the process, illustrated in FIG. 18, a smaller innertube 90 is placed inside the longitudinal bore of the remaining portionor portions of the outer tube 74. The inner tube 90 has an outerdiameter that generally corresponds to the inner diameter of the outertube 74. For example, the inner tube may have an outer diameter of about400 micrometers. The inner tube also has a longitudinal bore, which mayhave a diameter, for example, of about 200 micrometers. When the innertube 90 is placed inside the outer tube 74, the two tubes may be securedtogether, for example by welding the tubes together at the areasidentified by reference numerals 86 and 88.

After the two tubes are joined together, further cuts are made to formthe implant as shown in FIG. 19. This step includes simultaneouslycutting the outer tube and inner tube along an angled plane at theoutlet end of the implant to form the upper surface of the disk 84 andto cut away the unwanted portion of the inner tube 90 that wouldotherwise have projected beyond that upper surface of the disk 84. Theportion of the inner tube 90 that remains after these final cuts formsthe implant shaft. The portions of the outer tube 74 that remain afterthese final cuts form the retention projection 82 and the disk 84.

It will be appreciated by persons having ordinary skill in the art thatvariations on this manufacturing process and other manufacturingprocesses are possible. For example, an implant made of plastic may bemanufactured by a suitable molding operation.

Various mechanisms may be used, if desired, for giving different flowcharacteristics to the implant. It may be desirable to use implants withdifferent flow characteristics for different patients and/or to have animplant in which the flow characteristics may be changed afterimplantation in a particular patient.

FIGS. 20 through 25 illustrate various mechanisms for assisting incontrolling the flow of fluid, e.g., aqueous humor, through an implant100 according to the invention. In FIG. 20, the implant 100 has a flowcontrolling wire or rod 92A in the tube passage 102. The flowcontrolling rod 92A may be spot welded on one side to the inside of thetube passage 102.

The effect of the flow controlling rod 92A is to reduce thecross-sectional area through which the fluid flows for a particularlength inside the tube passage 102 of the implant 100. Because the flowis a function of the cross-section and length of the lumen through whichit passes, the interposition of the flow controlling rod 92A serves toincrease the resistance to flow. In an intraocular implant, for example,this assists in reducing the risk of hypotony.

The diameter of the flow controlling rod 92A may be selected inaccordance with the flow characteristics that are desired. For example,an internal tube passage of the implant having a diameter of 200micrometers may be fitted with a flow controlling rod 92A having adiameter that is, for example, between 175 micrometers and 195micrometers. A larger diameter for the flow controlling rod 92A providesmore resistance to flow.

The length and cross-sectional shape of the flow controlling rod maysimilarly be selected to achieve the flow characteristics that aredesired. FIGS. 21A through 21D show four possible cross-sectional shapesfor the flow controlling rod. Flow controlling rod 92A has a circularcross-section. Flow controlling rod 92B is similar to flow controllingrod 92A with the addition of grooves 94B. Flow controlling rod 92C has aflat surface 96C. Flow controlling rod 92D has a longitudinal bore 98D.

FIGS. 22 and 23 illustrate further possible modifications to the flowcontrolling rod to modify the flow characteristics. As shown in FIG. 22,the flow controlling rod 92E may have an external helical groove 99Egiving it a threaded appearance. If the diameter of the flow controllingrod 92E is large such that most or all of the flow occurs through thehelical groove 99E, this embodiment provides a longer path for the fluidto travel and thus a greater resistance to flow. Additionally oralternatively, as shown in FIG. 23, the flow controlling rod 92F may betapered or partially conical in shape. This embodiment provides lessresistance to flow toward the outlet end of the implant. Persons skilledin the art will appreciate that numerous other variations are possiblefor the shape and size of the flow controlling rod.

With the use of a flow controlling rod that is adjustable, the flowcharacteristics of the implant may similarly be adjustable. Thus, forexample, the flow controlling rod may be mounted within the tube passageby only a friction fit, so that its position within the tube passage maybe adjusted. As illustrated schematically in FIG. 24, the longitudinalposition of the flow controlling rod 92 may be adjusted to provide alonger or shorter distance d for the fluid to travel from the inlet sidehole(s) 104 to the end of the flow controlling rod 92. A longer distanced for the fluid to travel provides a higher resistance to flow. Anotherway to adjust the flow when using a flow controlling rod with anon-circular cross-section, as in FIGS. 21B and 21C, is to rotate therod within the tube passage. This rotation changes the orientation ofthe rod with respect to the side holes 104, giving different flowcharacteristics to the implant.

The flow characteristics of the implant may be adjusted beforeimplantation in accordance with the patient's needs, or, if desired, theimplant may be constructed to allow for the flow characteristics throughthe implant to be varied after the implant has been implanted. After theimplant has been implanted, the flow controlling rod 92 may be pushedforward toward the inlet end of the implant, for example by a tool witha wire. This reduces the distance d that the fluid must travel from theinlet side hole(s) 104 to the end of the flow controlling rod 92, andthus reduces the resistance to flow through the implant. Alternatively,a rod with a non-circular cross-section may be rotated afterimplantation.

Another way to have different flow characteristics is to have differentlocations or configurations of the side holes 104. Thus, differentmodels of the implant may have side holes in different locations and/orwith different configurations. Alternatively, a single implant may haveside holes which can be changed, for example by temporary occlusion ofone or more of the side holes. FIG. 25 illustrates an implant withoccluded side holes 104. The occlusion may be permanent or temporary.Temporary occlusion may be with an absorbable material or with amaterial that may be removed after implantation, for example by a toolor laser probe. In this way, the resistance to flow can be reduced afterimplantation.

The implant may additionally or alternatively be designed to givedifferent flow characteristics as a function of the fluid pressure. Theflow controlling rod or wire may itself be flexible or movable anddesigned to flex or move in response to the fluid pressure. For example,as shown in FIG. 26, the flow controlling rod 92G may be fixed at oneend 122 to a front end of the implant 100 with the other end 124 of therod 92G unattached and free to bend. Before implantation, the rod 92Gextends essentially parallel to the axis of the tube passage. Whenimplanted, pressure from the fluid through the side holes 104 causes therod 92G to flex, as indicated by the dashed lines. In this way, when thefluid pressure rises at the inlet end of the implant, the rod 92G bendsto allow greater flow.

Another related example is shown in FIG. 27. In that embodiment, thetube passage 102A is tapered and the flow controlling rod 92H is biasedwithin the tube passage 102A by a spring 126. The flow controlling rod92H is illustrated as tapered, but it will be appreciated that othershapes are possible. The spring 126 is shown as braced against a flange128 near the outlet end of the tube passage 102A, but it will beappreciated that it also may be attached on the opposite side of the rod92H near the inlet end of the tube passage 102A. When the fluid pressureincreases at the inlet end, the force on the rod 92H causes the spring126 to compress (or, if the spring is positioned on the opposite side ofthe rod, the force on the rod causes the spring to extend). The rod 92His thus displaced longitudinally toward the outlet end of the implant,to a position at which the cross-section of the tube passage 102A isgreater. Thus, the area through which fluid is allowed to flow isincreased, allowing greater flow. As persons skilled in the art willappreciate, other variations are possible in which the rod moves orflexes to increase flow in response to increased pressure at the inletend of the implant.

FIG. 28 illustrates an end portion of an alternative embodiment of adelivery device 110 according to the invention. The delivery device 110has a handle (not shown) and a rod-like instrument 112. In this case,the rod-like instrument 112 has central bore 114 in which is located aretractable wire 116. The retractable wire 116 is positioned forpenetrating a tube passage 102 of the implant 100 when the implant 100is attached to the delivery device 110. The delivery device 110 has aretention mechanism including an abutment surface 118 having an anglegenerally corresponding to that of the disk 106 of the implant 100 forpreventing the implant 100 from moving up the delivery device 110 duringimplantation and a hook 120 for preventing the implant 100 from movingdown the wire 116.

For implantation, the implant 100 is placed over the wire 116 with thewire 116 projecting into the tube passage 102 and with the abutmentsurface 118 abutting against the disk 106 with the hook 120 retainingthe disk 106 around the opposite side. FIG. 28 illustrates the end ofthe delivery device 110 in this condition, with the retention wire 116in its forward position.

After the implant is in position, the retention wire 116 is retractedout of the implant 100. FIG. 29 illustrates the end of the deliverydevice 110 with the retention wire retracted. With the retention wireretracted, the implant is free to slide away from the hook 120, allowingthe delivery device 110 to be withdrawn, leaving the implant in place.

As will also be appreciated by persons having ordinary skill in the art,the various embodiments of implants, methods of manufacture, deliverydevices, and methods for implantation described hereinabove are given byway of example only. Various changes, modifications and variations maybe applied to the described embodiments without departing from the scopeof the invention, defined by the appended claims.

1.-22. (canceled)
 23. A method of using a delivery device for implantingan intraocular implant, the method comprising the steps of: (i) using adelivery device comprising: a handle; a rod-like instrument having abore; a retractable wire located in the bore of the rod-like instrument;and a retention mechanism including an abutment surface for preventingthe implant from moving up the delivery device during implantation and ahook for preventing the implant from moving down the wire duringimplantation; (ii) directing the implant into the eye; (iii) retractingthe wire to release the implant from the delivery device; and (iv)withdrawing the delivery device.
 24. A method of using a delivery deviceaccording to claim 23 wherein the hook prevents movement of the implantin a direction parallel to the wire but permits movement in a directiontransverse to the wire, such that when the wire is retracted from a tubepassage of the implant, the implant is permitted to slide away from thehook to separate the implant from the delivery device.
 25. A method ofusing a delivery device according to claim 23 wherein the abutmentsurface has an angle generally corresponding to that of a disk of theimplant.
 26. A method of using a delivery device for implanting anintraocular implant, the method comprising the steps of: (i) using adelivery device comprising: a handle; a rod-like instrument having abore, the bore having a longitudinal axis; a retractable wire located inthe bore of the rod-like instrument; and an abutment surface forpreventing the implant from moving up the delivery device duringimplantation, the abutment surface being angled at a non-perpendicularangle relative to the longitudinal axis of the bore; (ii) directing theimplant into the eye; (iii) retracting the wire to release the implantfrom the delivery device; and (iv) withdrawing the delivery device. 27.A method of using a delivery device according to claim 26 wherein whenthe wire is retracted from a tube passage of the implant, the implant isseparated from the delivery device.
 28. A method of using a deliverydevice according to claim 26 wherein the abutment surface has an anglegenerally corresponding to that of a disk of the implant.
 29. A methodof using a delivery device for implanting an intraocular implant, themethod comprising the steps of: (i) using a delivery device comprising:a handle; a rod-like instrument having a bore; a retractable wirelocated in the bore of the rod-like instrument; and a hook forpreventing the implant from moving down the wire during implantation;(ii) directing the implant into the eye; (iii) retracting the wire torelease the implant from the delivery device; and (iv) withdrawing thedelivery device.
 30. A method of using a delivery device according toclaim 29 wherein the hook prevents movement of the implant in adirection parallel to the wire but permits movement in a directiontransverse to the wire, such that when the wire is retracted from a tubepassage of the implant, the implant is permitted to slide away from thehook to separate the implant from the delivery device.
 31. A method ofusing a delivery device according to claim 29 further comprising anabutment surface having an angle generally corresponding to that of adisk of the implant.